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Analysis of Water Condensation and Two-phase Flow in a Channel Relevant for Plate Heat Exchangers

In English

Författare

Redaktör

  • Bengt Sundén

Summary, in English

Water vapor condensation and two-phase flow appear in plate heat exchangers being used as condensers. Analysis of water phase change and flow dynamics is an important but complicated task due to large change in water physical/transport properties across the water liquid-vapor interface boundary. In particular, a singular-link behaviour in Navier-Stokes (N-S) equations is present due to the large step change in the density when computational simulation methods are applied. Conventional methods using ensemble averaged parameters such as void fraction are impossible to be applied to cases where high-resolution calculations and detailed analysis are required. In this study, a computational fluid dynamics (CFD) approach is presented for analysis of water vapor condensation and two-phase flow in a channel relevant for plate heat exchanger parallel plates. The developed model is based on the governing equations which are directly solved for the entire single- and two-phase fields. The water phase change and two-phase flow are treated by employing a water liquid-phase fraction factor based on the total enthalpy in each computational cell. The factor is defined as the ratio of the total enthalpy differential to the latent heat of condensation. The density, viscosity and conductivity of the two-phase region are calculated and updated based on the calculated value of the liquid-phase fraction factor until a converged result is reached. It is revealed that, among others, the inlet vapor velocity has significant effects on the water phase change and two-phase flow in the channel, in terms of liquid-water fraction factor distribution.

Avdelning/ar

Publiceringsår

2006

Språk

Engelska

Sidor

351-360

Publikation/Tidskrift/Serie

Advanced Computational Methods in Heat Transfer IX

Volym

53

Dokumenttyp

Konferensbidrag

Förlag

WIT Press

Ämne

  • Energy Engineering

Status

Published

ISBN/ISSN/Övrigt

  • ISBN: 1-84564-176-0